In a conventional design of this type (see Austrian Pat. No. 345 136, which corresponds to U.S. Pat. No. 4,210,342), the slide plate consisted of two parts. One of the parts has a recess therein for the two compression springs and the other part has the locking member designated for engagement with two toothed bars. Both parts are connected by a coupling. The locking member itself is held in engagement with the toothed bars by a screw.
Another object of the invention is to simplify the conventional construction and moreover to construct it more compactly, so that the entire apparatus is essentially oriented under the ski-binding part. This object is achieved according to the invention primarily by securing or resting on the slide plate extension member which extends in transverse direction of the apparatus and can be manually operated, through which extension member the locking member on the slide plate can become disengaged from the toothed bar of the guide rail against the force of the compression springs. Thus, the compression springs are used, aside from the usual urging of the ski-binding part toward the ski boot, to keep the locking member in engagement with the toothed bar, so that a separate screw for securing the locking member, which can be released or tightened only with difficulty and with a tool, is not needed. Therefore, the adjusting operation is substantially simplified, especially since for the adjustment, only a thumb is needed.
In order to assure an even force transmission of the two springs and to prevent a canting of the guide plate, according to a further characteristic of the invention the toothed bar is arranged in the center of the guide rail.
According to a different characteristic of the invention the extension member or a part of same is housed in a recess of the guide plate, which recess extends in transverse direction. In order for the extension member to provide appropriate leverage the extension member is as long as possible so as to overcome the spring forces. Further, the extension member is arranged in the region of a transverse plane which extends between one of the ends of the two springs engaging the guide plate, and the locking member. Should the force, which is applied by the extension member and comes from the compression springs, however, be reduced due to the fact that the extension member itself carries out a certain lever action at the start of the unlocking operation, then it is, however, sufficient to arrange the extension member in the region of the transverse plane which is placed through the ends of the springs which rest on the guide plate.
Of course the extension member and with it the locking member is sufficiently secured through the force of the two compression springs usually in the locked position of the apparatus. However, in extreme cases it may happen, that through a branch or the like which projects from the snow the extension member is operated unintentionally and thus the ski-binding part is released and longitudinal movement occurs. In order to also exclude these cases, a further development of the invention provides that the extension member is secured against an unintended movement in transverse direction of the apparatus.
Various possibilities are offered for the aforementioned type of lock as for example a push button which is biased by a spring and which must be pressed in prior to the extension member being able to be swivelled and moved in. However, it has been proven as a particularly simple construction if, according to the invention, the extension member is provided with a step which rests on the guide plate under the bias of the compression springs. In this manner, it is not necessary to use further elements for enhancing the securement.
To avoid an involuntary opening of the locking member, and according to a different characteristic of the invention, the step is arranged on the side of the extension member facing the end of the ski. The opening operation in this construction is initiated by a movement against the direction of travel of the ski.
Various constructive solutions are also possible for the design or shape of the extension member. Thus, according to a first inventive solution, the extension member has a slotted hole which extends in transverse direction and receives a bolt therethrough which is anchored on the guide plate and is positioned normally on same. The extension member carries a cam on the side which is associated with the slide plate, the transverse plane of which cam is spaced from the slotted hole and with which it slides along the slide plate as soon as it is pivoted about the axis of the bolt. After the swivelling operation is finished, when the extension member is so to speak in the unlocked position, the extension member can be pressed in unhindered and thus the locking member on the slide plate can be pressed out of engagement with the toothed bar.
According to a different inventive solution, the extension member has side surfaces which converge outwardly in a top view and has a front surface which, in a locked position, engages a side of the slide plate. A further step is provided on the side of the extension member remote from the first step and is supported under the pressure of the compression springs on a projection on the guide plate. If the extension member is to be unlocked, the second step is first moved along the projection, and at the same time the extension member is swivelled until the latter rests on the projection. A pressing in of the extension member is now easily possible in this position.
To assure a reliable resting of the thumb on the extension member and to prevent a sliding off of the same, the outer side of the extension member is inventively provided with an edging, the grooves of which extend vertically.